CN219142883U - Ultrasonic signal acquisition circuit - Google Patents

Abstract

The utility model discloses an ultrasonic signal acquisition circuit which comprises a primary amplifying module, a two-stage AGC amplifying module and a reference voltage module, wherein the primary amplifying module and the two-stage AGC amplifying module are connected with the reference voltage module; the two-stage AGC amplifying module comprises a first amplifying sub-module, an analog multiplier sub-module, a second amplifying sub-module and a rectifying feedback sub-module, wherein the first amplifying sub-module is connected with the primary amplifying module, the analog multiplier sub-module is connected with the second amplifying sub-module, and the first amplifying sub-module and the second amplifying sub-module are connected with the rectifying feedback sub-module. The ultrasonic signal acquisition circuit adopting the structure can acquire weak signals, meanwhile, the signal range which can be processed by the two-stage AGC amplifying module is larger, particularly, the ultrasonic signal acquisition circuit has better effect on signals with extremely small amplitude, and signals with ultrasonic Doppler signals of 1MHZ are processed, so that stable flow velocity signals are finally obtained.

Description

Ultrasonic signal acquisition circuit

Technical Field

The utility model relates to the technical field of ultrasonic signal acquisition, in particular to an ultrasonic signal acquisition circuit.

Background

The ultrasonic Doppler flow velocity signal has higher frequency, and is processed by a high-bandwidth signal conditioning circuit at present. The ultrasonic Doppler flow velocity signal frequency is higher, the quality requirements of the analog signal acquisition circuit and the analog power supply are higher, the noise of the analog circuit and the analog power supply must be controlled to be low, and therefore, more capacitors and inductors are inevitably used for filtering, and the size of the sampling circuit board is increased. The ultrasonic Doppler flow velocity signal is weak, the amplitude of the signal is about between 1uV and 50uV, the existing circuit adopts a cascade connection mode of a multi-stage operational amplifier and a multi-stage band-pass filter, the signal range processed by the existing ultrasonic Doppler flow velocity signal processing circuit is more than 100uV, the amplitude of an ultrasonic transmitting circuit is required to be increased to be more than 100V to drive an ultrasonic transducer in order to obtain a stable signal, the requirement on devices is high, and the damage probability of the devices is increased. Meanwhile, the AGC circuit adopts a primary AGC amplifying mode, the primary AGC gain amplifying times are limited, and when the signal amplitude is small, the AGC circuit is disabled.

Disclosure of Invention

The utility model aims to provide an ultrasonic signal acquisition circuit which can acquire weak signals, and meanwhile, a two-stage AGC (automatic gain control) amplification module can process signals with a larger range, particularly has a better effect on signals with extremely small amplitude, processes signals with ultrasonic Doppler signals of 1MHZ, and finally obtains stable flow velocity signals.

In order to achieve the above purpose, the utility model provides an ultrasonic signal acquisition circuit, which comprises a primary amplifying module, a two-stage AGC amplifying module and a reference voltage module, wherein the primary amplifying module and the two-stage AGC amplifying module are connected with the reference voltage module;

the two-stage AGC amplifying module comprises a first amplifying sub-module, an analog multiplier sub-module, a second amplifying sub-module and a rectifying feedback sub-module, wherein the first amplifying sub-module is connected with the primary amplifying module, the analog multiplier sub-module is connected with the second amplifying sub-module, and the first amplifying sub-module and the second amplifying sub-module are connected with the rectifying feedback sub-module.

Preferably, the primary amplifying module is a high-pass filtering amplifying circuit formed by an operational amplifier AD 8651.

Preferably, the first amplifying sub-module is composed of a first operational amplifier AD8338 and a first operational amplifier AD8130, the positive input end of the differential signal of the first operational amplifier AD8338 is connected with the output end of the operational amplifier AD8651, and the two output ends of the first operational amplifier AD8338 are connected with the input end of the first operational amplifier AD 8130.

Preferably, the analog multiplier sub-module is composed of a first operational amplifier AD8065, an analog switch CD4066, a two-stage low-pass filter circuit and a second operational amplifier AD8065,

the output end of the first operational amplifier AD8130 and the analog switch CD4066 are both connected with the input end of the first operational amplifier AD8065, the output end of the first operational amplifier AD8065 is connected with a two-stage low-pass filter circuit, and the two-stage low-pass filter circuit is connected with the input end of the second operational amplifier AD 8065.

Preferably, the second amplifying sub-module is composed of a second operational amplifier AD8338 and a second operational amplifier AD8130, the positive input end of the differential signal of the second operational amplifier AD8338 is connected with the output end of the second operational amplifier AD8065, and the two output ends of the second operational amplifier AD8338 are connected with the input end of the second operational amplifier AD 8130.

Preferably, the rectifying feedback sub-module is composed of a first operational amplifier LMC6484, a rectifying circuit and a second operational amplifier LMC6484,

the input end of the first operational amplifier LMC6484 is connected with the output end of the second operational amplifier AD8130, the output end of the first operational amplifier LMC6484 is connected with a rectifying circuit, the rectifying circuit is connected with the input end of the second operational amplifier LMC6484, the output end of the second operational amplifier LMC6484 is provided with two feedback ends, and the two feedback ends are respectively connected with the negative input end of the differential signal of the first operational amplifier AD8338 and the negative input end of the differential signal of the second operational amplifier AD 8338.

Therefore, the ultrasonic signal acquisition circuit adopting the structure has the following beneficial effects:

(1) The primary amplification module can collect weak signals.

(2) The built two-stage AGC amplifying module has a larger signal range, particularly has a better effect on signals with extremely small amplitude, processes signals with ultrasonic Doppler signals of 1MHz, and finally obtains stable flow velocity signals.

(3) And the negative feedback adopts a hardware self-adjustment mode, so that the adjustment speed is high and the precision is high.

(4) And an analog multiplier sub-module is built by an analog switch, so that the structure is simple and the control is convenient.

The technical scheme of the utility model is further described in detail through the drawings and the embodiments.

Drawings

Fig. 1 is a schematic diagram of an ultrasonic signal acquisition circuit according to the present utility model.

Detailed Description

Examples

Fig. 1 is a schematic diagram of an ultrasonic signal acquisition circuit according to the present utility model, and as shown in the figure, the ultrasonic signal acquisition circuit includes a primary amplifying module, a two-stage AGC amplifying module, and a reference voltage module, where the primary amplifying module and the two-stage AGC amplifying module are connected with the reference voltage module. The two-stage AGC amplifying module comprises a first amplifying sub-module, an analog multiplier sub-module, a second amplifying sub-module and a rectifying feedback sub-module, wherein the first amplifying sub-module is connected with the primary amplifying module, the analog multiplier sub-module is connected with the second amplifying sub-module, and the first amplifying sub-module and the second amplifying sub-module are connected with the rectifying feedback sub-module.

The primary amplifying module is a high-pass filtering amplifying circuit consisting of an operational amplifier AD 8651.

The first amplifying sub-module is composed of a first operational amplifier AD8338 and a first operational amplifier AD8130, the positive input end of the differential signal of the first operational amplifier AD8338 is connected with the output end of the operational amplifier AD8651, and the two output ends of the first operational amplifier AD8338 are connected with the input end of the first operational amplifier AD 8130.

The analog multiplier sub-module consists of a first operational amplifier AD8065, an analog switch CD4066, a two-stage low-pass filter circuit and a second operational amplifier AD8065, wherein the output end of the first operational amplifier AD8130 and the analog switch CD4066 are both connected with the input end of the first operational amplifier AD8065, the output end of the first operational amplifier AD8065 is connected with the two-stage low-pass filter circuit, and the two-stage low-pass filter circuit is connected with the input end of the second operational amplifier AD 8065.

The second amplifying sub-module is composed of a second operational amplifier AD8338 and a second operational amplifier AD8130, the positive input end of the differential signal of the second operational amplifier AD8338 is connected with the output end of the second operational amplifier AD8065, and the two output ends of the second operational amplifier AD8338 are connected with the input end of the second operational amplifier AD 8130.

The rectifying feedback sub-module is composed of a first operational amplifier LMC6484, a rectifying circuit and a second operational amplifier LMC6484, wherein the input end of the first operational amplifier LMC6484 is connected with the output end of the second operational amplifier AD8130, the output end of the first operational amplifier LMC6484 is connected with the rectifying circuit, the rectifying circuit is connected with the input end of the second operational amplifier LMC6484, the output end of the second operational amplifier LMC6484 is provided with two feedback ends (AD 8338_FB and AD8338_FB 1), and the two feedback ends are respectively connected with the negative input end of the differential signal of the first operational amplifier AD8338 and the negative input end of the differential signal of the second operational amplifier AD 8338.

The signal processing process is as follows:

the ultrasonic Doppler flow velocity signal enters an operational amplifier through a capacitor C1 of the primary amplification module, the C1 and the R1 form a high-pass filter, the cut-off frequency is 0.8MHz, and the operational amplifier AD8651 carries out primary amplification on the 0.8MHz signal by about 11 times, so that weak signals can be acquired.

Performing first-stage amplification: the filtered and amplified signal enters the first operational amplifier AD8338, the feedback voltage of the negative input end of the differential signal of the first operational amplifier AD8338 is AD8338_fb, the differential output ends OUTP and OUTM of the first operational amplifier AD8338 can keep the same amplitude within a certain range of the input signal, the bandwidths of the output signals can be limited below 1.6MHZ by the capacitors C2 and C3, the high-frequency signal is restrained, and the output signal of the first operational amplifier AD8338 is input into the first operational amplifier AD8130, so that the differential signal can be converted into a single-ended signal.

Signal conversion and amplification: the signal of the single-ended signal output by the first operational amplifier AD8130 and the signal of the standard 1MHz signal of the transmission signal are 0-5KHZ signals after passing through the analog multiplier submodule, and the output is amplified 3 times by the second operational amplifier AD8065 through the two-stage low-pass filter circuit.

Second stage amplification: and then the signal is processed by a second amplifying sub-module to output a single-ended signal AD8130_VOUT.

Amplifying and outputting: the single-ended signal AD8130_vout is amplified by the first operational amplifier LMC6484, and the output terminal LMC6484_vout1 of the first operational amplifier LMC6484 can obtain a stable flow rate signal.

Therefore, the ultrasonic signal acquisition circuit adopting the structure can acquire weak signals, meanwhile, the two-stage AGC amplification module can process signals in a larger range, particularly has a better effect on signals with extremely small amplitude, processes signals with ultrasonic Doppler signals of 1MHz, and finally obtains stable flow velocity signals.

Finally, it should be noted that: the above embodiments are only for illustrating the technical solution of the present utility model and not for limiting it, and although the present utility model has been described in detail with reference to the preferred embodiments, it will be understood by those skilled in the art that: the technical scheme of the utility model can be modified or replaced by the same, and the modified technical scheme cannot deviate from the spirit and scope of the technical scheme of the utility model.

Claims (6)

1. An ultrasonic signal acquisition circuit is characterized in that: the system comprises a primary amplifying module, a two-stage AGC amplifying module and a reference voltage module, wherein the primary amplifying module and the two-stage AGC amplifying module are connected with the reference voltage module;

the two-stage AGC amplifying module comprises a first amplifying sub-module, an analog multiplier sub-module, a second amplifying sub-module and a rectifying feedback sub-module, wherein the first amplifying sub-module is connected with the primary amplifying module, the analog multiplier sub-module is connected with the second amplifying sub-module, and the first amplifying sub-module and the second amplifying sub-module are connected with the rectifying feedback sub-module.

2. An ultrasonic signal acquisition circuit according to claim 1, wherein: the primary amplifying module is a high-pass filtering amplifying circuit consisting of an operational amplifier AD 8651.

3. An ultrasonic signal acquisition circuit according to claim 2, wherein: the first amplifying sub-module is composed of a first operational amplifier AD8338 and a first operational amplifier AD8130, the positive input end of the differential signal of the first operational amplifier AD8338 is connected with the output end of the operational amplifier AD8651, and the two output ends of the first operational amplifier AD8338 are connected with the input end of the first operational amplifier AD 8130.

4. An ultrasound signal acquisition circuit according to claim 3, wherein: the analog multiplier sub-module consists of a first operational amplifier AD8065, an analog switch CD4066, a two-stage low-pass filter circuit and a second operational amplifier AD8065,

the output end of the first operational amplifier AD8130 and the analog switch CD4066 are both connected with the input end of the first operational amplifier AD8065, the output end of the first operational amplifier AD8065 is connected with a two-stage low-pass filter circuit, and the two-stage low-pass filter circuit is connected with the input end of the second operational amplifier AD 8065.

5. The ultrasonic signal acquisition circuit of claim 4, wherein: the second amplifying sub-module is composed of a second operational amplifier AD8338 and a second operational amplifier AD8130, the positive input end of the differential signal of the second operational amplifier AD8338 is connected with the output end of the second operational amplifier AD8065, and the two output ends of the second operational amplifier AD8338 are connected with the input end of the second operational amplifier AD 8130.

6. The ultrasonic signal acquisition circuit of claim 5, wherein: the rectifying feedback sub-module consists of a first operational amplifier LMC6484, a rectifying circuit and a second operational amplifier LMC6484,

the input end of the first operational amplifier LMC6484 is connected with the output end of the second operational amplifier AD8130, the output end of the first operational amplifier LMC6484 is connected with a rectifying circuit, the rectifying circuit is connected with the input end of the second operational amplifier LMC6484, the output end of the second operational amplifier LMC6484 is provided with two feedback ends, and the two feedback ends are respectively connected with the negative input end of the differential signal of the first operational amplifier AD8338 and the negative input end of the differential signal of the second operational amplifier AD 8338.

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